Glowing mercury thyratrons: inside a 1940s Teletype switching power supply

Re:Glowing mercury thyratrons: inside a 1940s Teletype switc... by CamperBob2 on Monday September 10, 2018 @05:52PM (#17955534)

The krytrons I've seen are too small to conduct that much current. The Wikipedia article refers to kiloampere currents ( https://en.wikipedia.org/wiki/Krytron ) but I don't see how that would work with the tube in their photograph. At long duty cycles you'd either vaporize the electrodes or fuse the wires, and at short duty cycles the parasitic inductance would be the limiting factor.

Their main claim to fame is switching speed. I imagine that GaN FETs have finally rendered them obsolete, or will soon. Measuring these things is not entirely trivial ( https://www.edn.com/design/test-and-measurement/4437360/How-... ).

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Re:Glowing mercury thyratrons: inside a 1940s Teletype switc... by anfractuosity on Monday September 10, 2018 @05:58PM (#17955573)

https://nuclear-knowledge.com/detonators.php provides more information, they are designed for fast switching, but still at vast currents re. triggered spark gaps "Typically, compact versions of these devices rate at 20-100 KV, and 50-150 kiloamps, and the triggering potential is one-half to one-third the maximum voltage. Switch current rise times last 10-100 nanoseconds. "

For krytron's specifically it says 'These devices have maximum voltage ratings from 3 to 10KV, and peak current rating of 300-3000 amps' which would have been useful for detonating the exploding-bridgewire, which requires a hefty current.

Also I believe modern versions such as the following Thyratron https://www2.l3t.com/edd/pdfs/datasheets/L4906A.pdf are used with lasers. Peak current 20,000A. Peak voltage 35kV.

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